Burner apparatus



April 30, 1968 c, V E, JR 3,380,410

BURNER APPARATUS Filed Sept. 7, 1966 FIG; INVENTOR C. R. VENABLE,JR.FIG. 2

ATTORNEYS United States Patent 0 3,380,410 BURNER APPARATUS Charles R.Venable, Jr., Bartlesville, Okla, assignor to Phillips PetroleumCompany, a corporation of Delaware Filed Sept. 7, 1966, Ser. No. 577,6641 Claim. (Cl. 110-97) ABSTRACT OF THE DISCLOSURE Burner apparatuscomprises a hollow, tubular, horizontally disposed refractory linedchamber having planar lower interior side and bottom walls in thevicinity of 'a flame impingement baffle downstream of the burning zonein said chamber which bafile comprises a plurality of stackedcylindrical elements supported by said planar interior side and bottomwalls and being supported by frictional engagement between said elementsthe axes of which are parallel to the major axis of the burner chamber.

This invention relates to an improved burner apparatus. In one aspect, afuel burner comprises a tubular burner chamber having a fluid perviousimpingement baflle therein. -In another aspect, a hydrocarbon fuelburner comprises a horizontally disposed burner chamber having therein aflame impingement baffle comprising a plurality of tubular elements. Inanother aspect, a fuel burner comprises a horizontally disposed burnerchamber having therein a flame impingement baffle comprising 'aplurality of cylindrical elements, the axes of which are parallel toeach other and to the axis of the burner chamber.

Numerous sources of combustion energy, for example, low B.t.u.hydrocarbons, process off gas streams, etc., are often disposed of aswaste for the reason that they burn only under very severe conditions.In other instances, low quality hydrocarbon fuels are often onlypartially consumed in burners, hot blast stoves, furnaces and the like,The uncombusted fuel is in many instances vented as flue gas withoutrecovering the energy which would be realized by the combustion thereof.

I have found that the degree of combustion of low quality fuels can beimproved by conducting the combustion in a novel apparatus.

It is therefore one object of this invention to provide an improvedburner apparatus for the combustion of fuels. It is another object ofthis invention to provide an apparatus for burning low quality fuels. Itis yet another object of this invention to improve the degree ofcombustion of low quality fuels.

Other aspects, objects and several advantages of this invention will beapparent to one skilled in the art from a study of this disclosure, thedrawing and the appended claim.

In accordance with one embodiment of this invention, low quality fuelssuch as, for example, process off-gas streams, low B.t.u. hydrocarbonstocks, etc., which burn only with some difficulty under severeconditions, are burned in a horizontally disposed tubular burner havingtherein a fluid pervious flame impingement refractory bafiie immediatelydownstream of the combustion zone. The bafiie receives and accumulatesheat from combustion that takes place in the combuston zone andtransfers this heat to the uncombusted low quality constituents whichare either derived from the feed or produced in the combustion zoneupstream of the haflie. Heat is transferred from the baflie to theremaining uncombusted materials promoting the combustion thereof with aconsequent improvement in the overall degree of combustion.

3,380,410 Patented Apr. 30, 1968 The concept of this invention will bebetter understood by reference to the drawings, of which FIGURE 1 is across-sectional view of a burner which can be employed within theconcept of this invention, FIGURE 2 is an axial cross-section of theburner showing the impingement bafile and FIGURE 3 is an expandedcross-sectional view of the fluid pervious baflle of this invention.

Referring now to the drawings, FIGURE 1 is a crosssectional planarillustration of 'a fuel burner in which the concept of this inventioncan be employed. Low quality combustible fuel such as flue or waste gasor diflicultly combustible low B.t.u. hydrocarbon mixtures is preferablyemployed as feed to burner nozzle 2 by way of conduit 1. However, anysuitable combustible fuel, for ex ample, hydrocarbons having from 1 to20 carbon atoms can be employed. Air is drawn into the burner by way ofconduit 11 and is preheated by passage through conduits 5 which surroundthe burner. The air having been preheated enters the burning chamber 16by way of outlet 9 at which point it is admixed with fuel entering thesystem from nozzle 2. The mixture is burned in chamber 16 and hotcombustion products contact fluid pervious impingement baflie 7 afterwhich they exit the burner by way of conduit 10. These hot combustionproducts after leaving the burner can be employed for any desiredheating purpose such as, for example, solids drying, steam production,etc.

The furnace can comprise an outer metallic shell surrounding theperiphery of the burner and providing structural support for therefractory material contained therein. Outer insulating layer 4 composedof fire brick or other suitable high temperature refractory materialminimizes heat loss to the atmosphere and surrounds air preheatingconduit 5. Inner refractory layer 6 defines the combustion chamber,further insulates the system and conveys heat to air preheater 5. Fluidpervious refractory impingement baffle 7 comprises a plurality of thediscrete tubular elements .12 having passages therethrough. Theseelements are composed of any suitable refractory material capable ofwithstanding the flame temperatures within the burner. Suitablerefractory materials in this application are, for example, fire clay,high alumina, silicon carbide, high purity magnesia, stabilizedzirconia, zircon, mullite, and other refractories commonly used forburner block applications.

FIGURE 2 is a cross-sectional view of the interior of the furnaceshowing the honeycomb structure of the presently preferredfiuid'pervious impingement bafiie of this invention. The majority of theinterior wall of the burner 6 is constructed of fire brick beingpartially replaced by wedge brick 15 in the vicinity of the impingementb'alile. This construction provides a linear inclined wall 7 on eitherside of the lower burning interior surface which more adequatelyaccommodates the preferred orientation of cylindrical elements 12 whichare the presently preferred structural elements of which the baffle iscomprised. A linear horizontal lower support for the battle assembly 7is preferably provided as a ledge or threshold immediately underlyingthe baffle. The construction of ledge 13 can comprise any suitablerefractory material such as cut wedge brick similar to lateral supports15 or castable refractory as illustrated.

It is only necessary within the concept of this invention that thebaffle be comprised of a plurality of refractory elements which can beassembled to form a fluid pervious impingement baffle having relativelyhigh surface area and being of minor axial extent without the necessityof cementing or otherwise attaching individual elements to adjacentelements. Of course, these elements can be physically attached to eachother although an advantage of the presently preferred embodiment ofthis invention is that such structure is not required.

Although the presently preferred element configuration is cylindrical asillustrated due to ease of construction, desirable surface to volumeratios, ease of assembly and the durability of the resulting bafiie,numerous other shapes can be employed. Suitable cross-sectionalconfigurations are, for example, rectangular, triangular, etc., althoughthey need not be geometric.

FIGURE 3 is a cross-section showing the interior burner wall 6, thebaffle assembly 7 of a plurality of tubular elements while havingpassages therethrough 8. Lower support ledge 13 of said castablerefractory is also illustrated.

In operation, it is desirable that fluid pervious bathe 7 be locatedsufficiently downstream of fuel injection nozzle 2 so that most of therelatively combustible fuel is burned before contacting the leading faceof b'afiie 7. The remaining uncombusted fuel then contacts heated baffle7 which transfers suflicient heat to fuel contacting the baffle surfaceto promote its combustion. Depending on fuel composition, fuel-airratios and flow rates, the temperature of bafiie 7 will usually bewithin the range of from about 1800 F. to about 2800 R, whichtemperature is suflicient to substantially increase the degree ofcombustihon of relatively noncombustible materials found in low qualityfuels. Such fuels are, for example, off-gas from reactors used to makefurnace type carbon black, off-gas from the regenerator in a fluidcatalytic cracking unit, top gas from blast furnaces, waste gases fromopen hearth furnaces, 'and similar gases.

Numerous variations and modifications of the concept of this inventionwill be apparent to one skilled in the art in view of the foregoingdisclosure, the drawings and the appended claim to this invention, theessence of which is that there is provided an apparatus for burningfuels comprising a horizontally disposed tubular burner chamher havingtherein a fluid pervious refractory impingement baffle.

I claim:

1. Burner apparatus comprising a hollow, tubular, horizontally disposedrefractory lined burner chamber having fiuid hydrocarbon fuel inletmeans at a first axial extremity for injecting said fuel into saidchamber, air inlet means at said first axial extremity for injecting airinto said chamber, outlet means at the other axial extremity forpermitting the passage of combustion products from said chamber, fluidpervious refractory impingement baifie means positioned within saidchamber for receiving heat from the combustion of said fuel upstream ofsaid bafiie and transmitting said heat to uncombusted fuel contactingsaid bafile to burn s'aid uncombusted fuel, the lower interior side andbottom walls of the burner in the vicinity of the baffle being planar,the baffle comprising a plurality of discrete cylindrical elementsloosely stacked upon the planar interior side and bottom walls and beingsupported by frictional engagement between the elements, the axes of theelements being parallel to the axis of the chamber.

References Cited UNITED STATES PATENTS 1,080,368 12/1913 Reagan 110971,485,967 3/1924 Duncan 110-97 2,906,368 9/ 1959 Nelson.

FOREIGN PATENTS 2,781 1914 Great Britain.

JAMES W. WESTHAVER, Primary Examiner.

